After the Serbian
victory in the First World War by the end of 1918 Montenegro enters the
political union with Serbia under the Karadjordjevic dynasty. It is important
to stress that this resolved the long-standing dynastic rivalry between
the two Serb royal families: the Petrovic Njegos family of Montenegro and the
Karadjordjevic family of Serbia. The decision was taken at the historical Great
people's council of Podgorica on 26th of November 1918. The main decisions reached
at the event were: 1.) The unification of Serbia and Montenegro, 2.) dethronization
of King Nikola I Petrovic and the acceptance of the Karadjordjevic dynasty.
Although most Montenegrins (the Whites) were in fervor of these decisions,
one part of King Nikola's supporters (the Greens) wished to preserve the
Petrovic Njegos dynasty, and also wanted the union with Serbia but under completely
different terms (a federal union and not a centralized one). These groups got their
names according to the color of the session's voting sheets.

With support of Italy the Greens organized the Christmas Uprising in 1919 with the
aim to bring the Petrovic Njegos dynasty again on the Montenegrin throne. The rebellion
failed, the rebels fled to Italy, later returned and in June started unsuccessful guerrilla war.
In traces the Greens resisted till 1926 and after that their struggle was represented in
political program of Montenegrin Federalist Party: Montenegro, Serbia and other Yugoslavs
in federal state.

In the Second World War the Greens were organized again under Italian occupation command
and started the war against the communists. Soon they were disorganized and one group joined the
communist and another joined Serbian monarchists - the Chetniks. After the communist victory in 1945 many
leaders of the Greens were killed as the collaborationists of Italy.